The eyes A close up of a young person's eyes. The eyes are responsible for four-fifths of all the information our brain receives. Here you can find out a bit more about how they work, common problems that affect vision and the work Sightsavers does to treat and prevent avoidable blindness. You can also find out more about the people whose lives have been changed thanks to donations from people like you. How do eyes work? (click image to see enlarged version or click here for text alternative) Graphic of an eye with information about its different parts The images we see are made up of light reflected from the objects we look at. This light enters the eye through the cornea. Because this part of the eye is curved, it bends the light, creating an upside down image on the retina (this is eventually put the right way up by the brain). The retina is a complex part of the eye, but only the very back of it is light sensitive. This part of the retina has roughly the area of a 10p coin, and is packed with photosensitive cells called rods and cones. Cones are the cells responsible for daylight vision. There are three kinds – each responding to a different wavelength of light: red, green and blue. The cones allow us to see images in colour and detail. Rods are responsible for night vision. They are sensitive to light but not to colour. In darkness, the cones do not function at all. How do we see an image? The lens focuses the image. It can do this because it is adjustable – using muscles to change shape and help us focus on objects at different distances. The automatic focusing of the lens is a reflex response and is not controlled by the brain. Once the image is clearly focused on the sensitive part of the retina, energy in the light that makes up that image creates an electrical signal. Nerve impulses can then carry information about that image to the brain through the optic nerve.

A heart attack is a medical emergency. A heart attack usually occurs when a blood clot blocks blood flow to the heart. Without blood, tissue loses oxygen and dies. Symptoms include tightness or pain in the chest, neck, back, or arms, as well as fatigue, lightheadedness, abnormal heartbeat, and anxiety. Women are more likely to have atypical symptoms than men. Treatment ranges from lifestyle changes and cardiac rehabilitation to medications, stents, and bypass surgery.

Ankle fusion (arthrodesis) This is a surgical procedure which joins together the main bones of the ankle joint (the tibia and the talus). However, depending on the technique your surgeon will use, occasionally the fibula will be included in this procedure. The two joint surfaces which generate the pain are removed.

Embryonic cardiovascular system. ... The human arterial and venous systems develop from different embryonic areas. Aortic Arches. The aortic arches—or pharyngeal arch arteries—are a series of six, paired, embryological vascular structures that give rise to several major arteries .

An intelligence quotient (IQ) is a total score derived from one of several standardized tests designed to assess human intelligence. IQ is a number meant to measure people cognitive abilities (intelligence) in relation to their age group. An I.Q between 90 and 110 is considered average; over 120, superior. Roughly 68% of the population has an IQ between 85 and 115. The average range between 70 and 130, and represents about 95% of the population.

The rotator cuff is a group of muscles and tendons that surround the shoulder joint, keeping the head of your upper arm bone firmly within the shallow socket of the shoulder. A rotator cuff injury can cause a dull ache in the shoulder, which often worsens when you try to sleep on the involved side. Rotator cuff injuries occur most often in people who repeatedly perform overhead motions in their jobs or sports. Examples include painters, carpenters, and people who play baseball or tennis. The risk of rotator cuff injury also increases with age. Many people recover from rotator cuff disease with physical therapy exercises that improve flexibility and strength of the muscles surrounding the shoulder joint. Sometimes, rotator cuff tears may occur as a result of a single injury. In those circumstances, medical care should be provided as soon as possible. Extensive rotator cuff tears may require surgical repair, transfer of alternative tendons or joint replacement.

Cancer starts when cells in a part of the body begins to grow out of control and can spread to other areas of the body. There are many kinds of cancer. Cells in nearly any part of the body can become cancer. To learn more about how cancers start and spread, see What Is Cancer? Leukemias are cancers that start in cells that would normally develop into different types of blood cells. Here we will talk about acute myeloid leukemia (AML). Acute myeloid leukemia (AML) has many other names, including acute myelocytic leukemia, acute myelogenous leukemia, acute granulocytic leukemia, and acute non-lymphocytic leukemia. “Acute” means that this leukemia can progress quickly if not treated, and would probably be fatal in a few months. “Myeloid” refers to the type of cell this leukemia starts from. Most cases of AML develop from cells that would turn into white blood cells (other than lymphocytes), but some cases of AML develop in other types of blood-forming cells. The different types of AML are listed in “ How is acute myeloid leukemia classified?” AML starts in the bone marrow (the soft inner part of certain bones, where new blood cells are made), but in most cases it quickly moves into the blood. It can sometimes spread to other parts of the body including the lymph nodes, liver, spleen, central nervous system (brain and spinal cord), and testicles. Other types of cancer can start in these organs and then spread to the bone marrow. But these cancers that start elsewhere and then spread to the bone marrow are not leukemias. Normal bone marrow, blood, and lymphoid tissue To understand the different types of leukemia, it helps to know about the blood and lymph systems.

Multiple endocrine neoplasia type 2 (MEN2) (also known as "Pheochromocytoma and amyloid producing medullary thyroid carcinoma", "PTC syndrome," and "Sipple syndrome") is a group of medical disorders associated with tumors of the endocrine system. The tumors may be benign or malignant (cancer).

Multiple endocrine neoplasia type 2 (MEN2) is a hereditary condition associated with three primary types of tumors: medullary thyroid cancer, parathyroid tumors, and pheochromocytoma. MEN2 is classified into three subtypes based on clinical features. MEN2A, which affects 60% to 90% of MEN2 families Medullary thyroid cancer: 98% to 100% with MEN2A are affected Pheochromocytoma, a typically benign (noncancerous) tumor of the adrenal glands: 50% with MEN2A affected Parathyroid adenoma (benign tumor) or hyperplasia, meaning increased size, of the parathyroid gland: 5% to 10% with MEN2A affected MEN2B, which affects 5% of MEN2 families Medullary thyroid cancer: 98% to 100% with MEN2B affected Pheochromocytoma: 50% with MEN2B affected Mucosal neuromas, which is a benign tumor of nerve tissue on the tongue, lips and throughout the gastrointestinal tract: 95% to 98% affected Digestive problems caused by disordered nerves in the gastrointestinal tract: 75% to 90% affected Muscle, joint, and spinal problems: 95% affected Typical facial features, including swollen lips and thick eyelids: 75% to 90% affected Familial medullary thyroid cancer (FMTC), which affects 5% to 35% of MEN2 families Medullary thyroid carcinoma only Sources: Gagel RF, Marx SJ. “Multiple endocrine neoplasia.” Williams Textbook of Endocrinology, Chapter 40, 11th ed., Philadelphia, 2008, and Eng C, Clayton D, et al. Grubbs EG, Gagel RF. My, How Things Have Changed in Multiple Endocrine Neoplasia Type 2A! J Clin Endocrinol Metab 100(7):2532-5, 7/2015. PMID: 26151398. What causes MEN2? MEN2 is a genetic condition. This means that the cancer risk and other features of MEN2 can be passed from generation to generation in a family. The gene associated with MEN2 is called RET. A mutation (alteration) in the RET gene gives a person an increased risk of developing medullary thyroid cancer and other tumors associated with MEN2.

Neurosyphilis is an infection of the brain or spinal cord caused by the spirochete Treponema pallidum. It usually occurs in people who have had chronic, untreated syphilis, usually about 10 to 20 years after first infection and develops in about 25%–40% of persons who are not treated. The United States' Centers for Disease Control and Prevention (CDC) advises that neurosyphilis can occur at any stage of a syphilis infection.

Surgical Skin Closure Procedures

Treatment of periodontal disease - Scaling and root planing

ARDS was recognized as the most severe form of acute lung injury (ALI), a form of diffuse alveolar injury. The AECC defined ARDS as an acute condition characterized by bilateral pulmonary infiltrates and severe hypoxemia in the absence of evidence for cardiogenic pulmonary edema. The severity of hypoxemia necessary to make the diagnosis of ARDS was defined by the ratio of the partial pressure of oxygen in the patient’s arterial blood (PaO2) to the fraction of oxygen in the inspired air (FiO2). ARDS was defined by a PaO2/FiO2 ratio of less than 200, and in ALI, less than 300. This definition was further refined in 2011 by a panel of experts and is termed the Berlin definition of ARDS. [3] ARDS is defined by timing (within 1 wk of clinical insult or onset of respiratory symptoms); radiographic changes (bilateral opacities not fully explained by effusions, consolidation, or atelectasis); origin of edema (not fully explained by cardiac failure or fluid overload); and severity based on the PaO2/FiO2 ratio on 5 cm of continuous positive airway pressure (CPAP). The 3 categories are mild (PaO2/FiO2 200-300), moderate (PaO2/FiO2 100-200), and severe (PaO2/FiO2 ≤100).

TUMOR FRONTO ORBITARIO NEUROCIRUGÍA

To diagnose COPD, your doctor will probably do the following tests: Medical history and physical exam. These will give your doctor important information about your health. Lung function testsLung function tests, including an FEV1 test. These tests measure the amount of air in your lungs and the speed at which air moves in and out. Spirometry is the most important of these tests. Chest X-rayChest X-ray. This helps rule out other conditions with similar symptoms, such as lung cancer.

Kidney transplant surgery carries a risk of significant complications, including: Blood clots Bleeding Leaking from or blockage of the tube (ureter) that links the kidney to the bladder Infection Failure of the donated kidney Rejection of the donated kidney An infection or cancer that can be transmitted with the donated kidney Death, heart attack and stroke

The journey of egg and sperm. There are a lot of casualties (deaths) among the sperm as they swim toward the egg. First, many get lost in the maze of a woman's uterus where they also have to contend with acidic vaginal secretions.

Surgical Repair of Pectus Excavatum. Pectus excavatum is a condition in which a person's breastbone is sunken into his or her chest.

Vediographic-Electric Beat-Pacemakers and the human heart

Learn the basics of ECG (EKG) in one minute